FCC will allow unlicensed devices in analog TV spectrum

The Federal Communications Commission this week announced its roadmap for …

The FCC has just announced the roadmap (PDF) for giving unlicensed wireless devices access to empty "white spaces" in the current analog TV spectrum. US spectrum is at a premium (just consider the astronomical fees paid by cell phone providers to grab a chunk of it), and the FCC wants to ensure that space is available for innovative unlicensed technology.

The goal is to replicate the success of WiFi, but with longer range. The sub-900MHz band is an especially desirable bit of electromagnetic real estate because of its propagation characteristics—it travels easily through walls. Just think about the range offered by traditional television stations; it's not uncommon for viewers 25-30 miles out from a tower to receive good-quality signals. This is coverage that devices using the 2.4GHz band and higher simply can't match.

The FCC's goal is to have the new devices in the hands of consumers early in 2009, just after the completion of the transition to digital TV on February 17 of that year. To achieve it, their internal laboratory will start doing interference testing to see if unlicensed devices have the potential for interfering with DTV broadcasts and other radio services (radio astronomers successfully lobbied for the use of channel 37 forty years ago, for instance, and still have it today).

In October of 2007, the Commission will specify the final technical requirements for all unlicensed devices that operate in the TV bands. In December, the FCC laboratory will accept applications for certification of these devices, which will be available for sale after February of 2009.

Because these frequencies are used by so many applications (and will apparently be auctioned off after the TV stations vacate them), the FCC has a special set of rules for the unlicensed devices. Unlike WiFi or cordless phones, the new devices must contain a geo-location method like GPS and must be capable of "phoning home" to check in with an official database. That database will tell them which frequencies are available in any given geographic area. The alternative is professional installation (presumably, the installer would do this checking and configuration).

Spectrum sensing may also be required, though no technical specifications have yet been issued. This is a "listen first, then broadcast" technology that would require unlicensed devices to listen for an empty bit of spectrum before blasting out radio transmissions.

The roadmap certainly pleases the consumer electronics industry, which will no doubt make a killing by selling longer-range networking products. The broadcasters are less excited about it, but have expressed approval of the FCC's careful approach to allowing the new technology. David Rehr, CEO of the National Association of Broadcasters, said, "NAB has been working diligently with the Senate Commerce Committee on the unlicensed devices issue, along with the FCC. We are pleased the FCC has taken the sensible position of ensuring that these devices will be tested rigorously, and that no marketplace introduction will occur until after broadcasters complete a successful transition to digital television."

While deployments of the new technology will face significantly more hurdles then rolling out new devices in a totally unregulated band, the benefits of the sub-900MHz spectrum should make the inconvenience worthwhile. The FCC hopes the move will spur adoption of long-range wireless Internet, especially in rural areas which are likely to have plenty of open spectrum.